The Place Promised in Our Early Days
雲のむこう、約束の場所 (original)
In a post-war alternative timeline, Japan is divided into the North, controlled by the Union, and the South, controlled by the United States. A mysterious high tower rises within the borders of the Union. Three high school students promise to cross the border with a self-built airplane and unravel the secret of the tower.
Starring Hidetaka Yoshioka, Masato Hagiwara, Yuuka Nanri, Unsho Ishizuka, Kazuhiko Inoue, Risa Mizuno, Hidenobu Kiuchi, Masami Iwasaki, Eiji Takemoto, Takahiro Hirano
Watch "The Place Promised in Our Early Days" on Netflix released in 2004. It's a animation and drama movie, and has a rating of 6.9 out of 10 from Imdb which is usually fine for this kind of movie.